Method of casting and subsequently deburring of workpieces and a device for carrying out the method

ABSTRACT

A method of producing castings and subsequently deburring and also machining the castings if necessary. According to this method, the castings are removed from a casting machine while still in a hot state and conveyed by a gripper assembly to a deburring machine. This machine includes a pattern device into which the hot casting is placed. The device is slowly closed as the casting cools thereby shrinking the casting upon the pattern. As a result, appreciable deformation of the casting is effectively prevented. When the casting is substantially cooled and has thus reached its final configuration it is deburred in the deburring machine and if necessary surface finished. There is also disclosed a device for carrying out the aforedescribed casting and deburring steps in automated sequence.

' tee 1 atent 1 1 Jan. 15, 197% ['76] Inventor: Walter Reis,Frankenstrasse l,

Obernburg, Germany 1221 Filed: Apr. 27, 1972 1211 Appl. No.: 248,051

[30] Foreign Application Priority Data Hall 29/5275 Morel et al.29/527.6 X

Primary Examiner-Richard J. Herbst Assistant Examiner-D. C. Reiley, IIIAttorneyFrederick E. Hane et al.

[57-] ABSTRACT A method of producing castings and subsequently deburringand also machining the castings if necessary. According to this method,the castings are removed from a casting machine while still in a hotstate and conveyed by a grip-per assembly'to' a deburring machine. This'machine includes a pattern device into whichthe hot' casting is placed.The device is slowly closed as the casting cools thereby shrinking thecasting upon. the pattern. As a result, appreciable deformation of thecasting is effectively prevented. When the casting is substantiallycooled and has thus reached its final configuration it is deburred inthe deburring machine and if necessary surface finished.

There is also disclosed a device for carrying out the afore-describedcasting and deburring steps in automated sequence.

10 Claims, 7 Drawing Figures PATENTEDJAMSW SHEET 1 3 3,785,0-

SHiET E OF 3 PMENTEHJAM 15 I974 1 METHOD OF CASTING AND SUBSEQUENTLYDEBURRING OF WORKPI-ECES AND A DEVICE FOR CARRYING OUT THE METHOD Thepresent invention relates to a method of casting and deburringworkpieces, and particularly to a method of casting and deburringworkpieces in an automated operation. The invention further relates to adevice for casting and deburring workpieces.

BACKGROUND It is well known that the quality of the cast and thedeburred workpieces is strongly affected by the uniformity of the cycleof operation. In particular, the uniformity of the operationalcycle isimportant with respect to the caloric conditions in the casting molds.Temperature variations in the molds result in a considerable reductionof the useful life of the molds, and moreover, affect very much theshrinkage percentage and thus the obtainable tolerance accuracy of thecastings.

In view of the criticality between uniformity of the operational cycleand temperature control, various devices for withdrawing the castingsfrom the casting machine have been developed. There are known, forinstance, removal devices which grip the castings after opening of thehalves of the casting molds and then carry the removed casting from thecasting cavity of the casting machine. Subsequently, the castings aredeposited on a conveyor or in a delivery station.

Various types of automated grippers have been developed which areprogrammed to perform a sequence of functions. This programming maycontrol the grippers to dip a casting into a coolant bath andsubsequently to deliver the cooled casting to a deburring or flashingpress. I

The linking of an extrusion casting machine and of a subsequentdeburring or flashing machine by an automated gripper assembly as nowknown, has various technical disadvantages and is also economicallyburdensome in that the installation costs for such automated system arevery high.

The cooling of the castings either by air flow or by liquid flow or bydipping into a bath results in tensional differentials which may cause adistortion of the castings. To avoid such distortions it is known toplace the castings in a gauging block device. Obviously, the resultingadditional operations cause an increase in the overall costs of theoperation or make it even impossible to automate the entire operationwith the means now available for the purpose, the more so as the presenttrend in industry is to reduce more and more the time allocation for theoperational cycle. The result is that there is not sufficient timeavailable in the cycle for removing a casting automatically from thegauging device and then delivering the casting to a deburring orflashing machine. Moreover, during the cooling, residues and wastedeposits may form on the casting which subsequently must be removed inmany instances.

Dipping of castings, especially aluminum alloy castings into a coolanttends to cause a surface hardening of the castings. This is undesirableas in most instances a subsequent machining is necessary such asstamping, milling, drilling, threading, etc. Obviously, hardening of thesurface increases the required machining time.

THE INVENTION It is a broad object of the invention to provide a noveland improved method of casting and deburring workpieces which permits asubstantial reduction of the overall installation costs and alsoeliminates at least in most instances the need for gauging devices.

It is a further broad object of the invention to provide a novel andimproved device for producing castings and subsequently deburring and/orotherwise machining the casting.

SUMMARY OF THE INVENTION The aforepointed out objects, features andadvantages, and other objects, features and advantages which will bepointed out hereinafter, are obtained by removing a produced castingfrom the casting machine by a conveying and gripping assembly while itis still hot and placing the casting into a deburring or flashingmachine. While the casting is cooling in thismachine it is shrunk upon apattern means in the deburring machine by slowly closing the patternmeans in correlation with the cooling of the casting. Finally, thecasting is deburred or flashed while it is shrunk upon the'patternmeans.

An installation according to the invention comprises a preferablyhorizontally arranged deburring machineand a gripping and conveyingassembly. The deburring or flashing machine with reference to theextrusion casting machine for supplying castings to the deburringmachine can be selected as convenient by a suitably arranged movement ofgripper arms of the gripping means. In other words, the casting machineand the deburring machine can be placed in relative positions which aremost suitable for the specific conditions involved.

A particularly suitable and convenient arrangement is a position whichpermits placement of the working spaces in the casting machine and thedeburring machine side-by-side and parallel to the discharge directionsof both machines.

It is essential for the concept of the invention that a casting removedfrom the casting machine is immediately and without interruptionconveyed to the working space in the deburring machine. The manner inwhich such immediate conveyance is effected is usually not critical. Forinstance, for moving castings gripping assemblies may be used which aremounted posterior of the deburring machine and can be inserted throughthe opened deburring machine into the also opened casting machine andwithdrawn in the same manner. It is also possible to arrange for bothmachines an overhead conveyor which removes castings by suitablydisposed gripper means and then inserts such castings into the deburringmachine. It is essential that the hot castings are now placed into atool which is not designed for hot working but for cold working such asworking at room temperature.

A very important advantage of the invention resides in that maintenanceof close tolerances is possible and that the deburring or flashing toolsdo not have to be specially designed since the castings can be machinedto the desired true dimensions at room temperture. The shrinkingprocesses of the castings are not completed due to the elevatedtemperature which the casting has immediately after removal from thecasting machine (generally in practice between to 400C). Insertion ofsuch hot castings into a machining in the deburring machine is notpractical. Accordingly, conical pins or otherwise shaped locatingelements are provided on the casting if not already present to permitconvenient preliminary centering of the casting. After insertion of thehot and thus still over-dimensioned casting into the device forpreliminary centering the same, the deburring machine is closed to anextent such that the casting can be pressed by means of suitable counterholders into its preliminarily centered position.

After such closing of the deburring machine, the grippers holding thecasting are released and can now be withdrawn from the deburring cavityof the deburring machine.

Simultaneously -wi th the pressing of the casting by means of thecounter holders into the device for preliminarily centering, cooling ofthe casting begins. The cooling can be effected by natural heatdissipation or it can be assisted by suitable blowers. In special cases,forced cooling by use of liquid coolant is also suitable. Such coolingis effected while the gripping means are again moved into a readyposition for accepting the next casting. After a selectable period oftime, the deburring machine can be further closed and the casting,depending upon the shrinking process, can be pressed into a workingspace of a machining tool. Additionally, the counter-holding force mustbe adjusted in accordance with the requirements. Such adjustment can beeffected by continually or step-wise slowly closing the deburringmachine or by a preselected increase in the closing pressure.

Due to the progress of the cooling of the casting the same is now ready,assisted by the holding pressure, to slide into or upon the patternmeans of the deburring machine in which it remains until it is fullycooled and in which it is forced into its predetermined configuration ina manner similar to which occurs in a conventional gauging block device.

When this condition is accomplished, a final machining is effected,either by flashing off any protrusions, lugs, excess material, removalof surface irregularities, etc. This process can be continued by finalsurface finishing in a conventional manner.

After completion of all machining, the deburring machine is opened; thecasting and all waste material are removed and the deburring machine isnow ready for machining the next casting.

If it be desirable to keep the operational cycle as short as possible,for instance if very rapid sequence of castings is necessary, theclosing of the pattern means, the positioning of the locating means andthe cooling process can be simultaneously accelerated by the use ofsuitable coolants which may be liquid or gaseous. With such acceleratedcycle it is essential to provide for the deburring or flashing steps andsometimes also for the finishing operations a suitable selection ofmaterials and corresponding construction methods.

The method as hereinbefore described results due to a controlled rapidcooling in the production of castings substantially free of distortionswhich simultaneously can be deburred or flashed into the pattern meansalso used for correcting or preventing distortions. In this connectionit should be pointed out that in comparison with the tolerance accuracyobtainable with the heretofore conventional deburring at hightemperatures a much closer tolerance can be readily accomplished, and incomparison with the deburring of cooled castings as heretofore practicedan operational simplification is obtained, and thus a saving in theprocess steps and devices required for carrying out the process steps.

Moreover, the cooling progress can be so controlled that, for instance,inlet spouts of substantial crosssectional area for the casting materialand tap spouts need not to be forcibly cooled. An immediate return ofstill hot metal waste into the melting furnace is quite possible therebyreducing the required energy output. Forced cooling by using of liquidcoolants can be so controlled that the residual heat of the castings andother parts effects evaporation of the coolant.

It is further within the concept of the invention that the holders forthe finishing or cutting tools and available surfaces are utilized asheat exchangers. In such case, provisions must be made for an efficientdissipation of the heat, for instance by providing suitably placed ductsor channels through which a suitable coolant is directed.

To sum up, the following advantages are obtained among others:

A fully automated production and considerable saving oflabor areobtained. Operations can be carried out in a uniform casting cycle. Bycontrolling cooling of castings in correlation with the opening of thecasting machine and of the deburring machine, castings are obtainedwhich are substantially uniform and free of distortion without requiringthe use of a special gauging device. Careful orientation of the castingsis not necessary since by clamping the workpiece in the deburringmachine with its preselected pressure and by accurately guiding of thecastings in the machining means arbitrary and uncontrolled shrinking anddistortions are precluded. The removal of castings from the castingmachine can be effected at an earlier stage than heretofore possiblesince the deburring machine also effects gauging of the casting. As aresult, the casting cycle can be correspondingly accelerated.

ln comparison with the heretofore customary deburring or flashing at hottemperatures, closer tolerances are readily obtainable. In comparisonwith the heretofore also used cold deburring or flashing the importantadvantage of full automation and corresponding reduction in theproduction costs are obtained.

DETAILED DESCRIPTION OF THE INVENTION In the accompanying drawings,several embodiments of the invention are shown by way of illustrationand not by way of limitation.

In the drawing:

FIG. 1 is a sectional side view ofa casting and deburring installationaccording to the invention taken on line 1-1 of FIG. 2;

FIG. 2 is a sectional edge view of the installation of FIG. 1 taken online 22 of FIG. 1;

FIG. 3 is a sectional side view of a modification of the installationtaken on line 33 of FIG. 4;

FIG. 4 is a sectional edge view of FIG. 3 taken on line 4-4 of FIG. 3;

FIG. 5 shows schematically and partly in section a deburring deviceaccording to the invention, the left side of the figure showing thedevice in a first lowered position and the right side in a fully closedposition;

FIG. 6 is a detail of FIG. 5 on a larger scale; and

FIG. 7 is a side view of a machining tool to be used in conjunction withthe deburring device of FIG. 5.

FIG. 1 shows diagrammatically a horizontally disposed generallyconventional casting machine 1 which may be an extrusion castingmachine, an injjection casting machine, etc. The mounting guides of themadeburring maching 2 mounts on the guides 3 connected with it onconveying and gripping means 4 which carries at its ends suitablegrippers 5. The gripper means are controlled from a suitable controldevice (such as control device 19 of FIG. 3) so that the grippers 5 canbe opened and closed and that the gripper means is movable in thedirection of the arrows 6 and also in the direction of the arrows 7 as aunit. The gripper means 4 serves to lift a casting out of the castingmachine 1 and to insert it slowly into a hereinafter further describedtool of the deburring machine 2.

In the embodiment according to FIGS. 3 and 4, the conveying and grippingmeans 14 are not shown as in the previous embodiment at about themid-level of the casting machine and the deburring machine but above thetop level of the same. The casting machine 11 is merely indicated bycomponents adjacent to its mold II. A deburring machine 12 operating ina generally conventional manner is disposed parallel with the castingmachine.

A guide rail 13 is fixedly secured on the deburring machine 12 and aconveying and gripping means is guided on guide rails 13. The grippingmeans comprise a carrier or slide arrangement 14, 14' with a built-indrive means. The slide 14 is movable in the direction of arrow 16 andthe support arm of the gripper is slidable in the direction of the arrow17. Further support rails 13a are movable in the direction of arrow 18.The gripper can be opened and closed.

The afore-referred to movements are controlled by a control device 19via a control conduit 20. This control device is connected with thedeburring machine. The casting machine is connected to the controldevice 19 via a control conduit 21. The deburring machine is alsocontrolled as to its working cycle by this control device. The controldevice 19 should be visualized as a conventional device; many suitabletypes of control devices are well known in the art. It may be aservo-motor system, an electrical switching system or an electronicsystem. As it is evident, there must be available two operations foreach function, such as opening or closing of a gripper. Buttons foractivating the device are indicated at 190.

The gripping means take a completed but still hot casting out of thecasting machine and insert it into the deburring machine for cooling andsubsequent deburring.

In practice, it is necessary to lubricate the mold in the castingmachine and/or to smooth casting holder in the deburring machine. Thisis usually manually effected. According to the invention, the existingcontrol device and the guide rails for the gripping means are furtherused to guide and control a finishing device.

The finishing device comprises a slide assembly 24, 241', correspondingto the slide or carrier assembly 14, 14' with guide rails 24a and 25which are movable in the directions of arrows 16, 17 and 18. The guiderail 25 mounts a nozzle arrangement 26 which via a conduit 27 issupplied with a finishing agent such as a lubricant. The control ofslide 24 or 24 and the afore-indicated movements is effectedautomatically via a conduit 27 by control device 19 in the sequence ofthe working operations of the shown coupling of the machines.

The casting machine and the deburring machine do not have to be arrangedas shown in the horizontal position. The invention is, of course, alsoapplicable to upright disposed machines.

In FIG. 5 a casting is designated by 120, a lower pattern half by 121and an upper pattern half by 122. Each of these two pattern halves areparts of a pattern which has a lower half 123 and an upper half 124. Thetwo halves of the pattern are preferably held in position by springs125, or can be controllably driven by suitable pistons 126 acting uponthe pattern.

The pattern further comprises holder pins 127 and 128 for holdingtherebetween the casting by engaging burrs 29 thereon. Holders 127 and128 also serve for centering the casting by means of recesses 30engageable with noses 33 on burrs 29. The holders may be spring-loadedrelative to the casting as it is indicated by' springs 31, or they maybe provided with separate drive pistons 32. Recesses 30 are so disposedthat the noses 33 can just enter the recesses when the casting is stillhot and thus expanded, and that when the pattern half 122 is finallysettled upon the casting the same is clamped with a close fit betweenpattern halves 121 and 122. Deburring can now proceed in a conventionalmanner.

The deburring machine can be provided with cooling ducts 40. Instead of,or in addition, a cooling device 41 for spraying a coolant or a device42 for directing steam upon the casting can be provided.

As shown in FIG. 7, the deburring machine can additionally be providedwith machining devices such as, for instance, a milling tool 43 which iscontrolled by a drive piston 44 and serves to mill out an opening 45 inworkpiece 20 to the desired dimensions. As it is evident, the patternhalf122 must be lifted before opening 45 can be milled.

The operation of the illustrated and described installation may besummed up as follows:

1. Gripper 5 or 15' moves the casting 120 into the open pattern meansshown in FIG. 5 and holds it tight in this means.

2. The holder pins 127 and 128 move into the position shown on the lefthalf of FIG. 5.

3. Gripper 5 or 15' releases the casting and is again moved toward thecasting machine.

4. Pattern halves 121 and 122 move into the positions shown on the lefthalf of FIG. 5.

5. The pattern halves 121 and 122 are moved slowly and with littlepressure into engagement with casting 120.

6. The holders 127 and 128 are moved into the position shown on theright half of FIG. 5 while the casting is cooling and shrinking.

7. When casting 120 has sufficiently cooled, pattern halves 121 and 122are moved toward each other under heavy pressure thereby exertingcorresponding pressure against the casting thus forcing the same intoits final shape.

8. The deburring or flashing member 124 is now low- I ered and cuts offthe overhanging burrs 29 on the casting.

9. Pattern halves 121 and 122 are again reopened and holders 127 and 128are withdrawn. The finished casting now drops downwardly out of thedeburring machine.

It is obvious that details of the invention can be varied in accordancewith the specific purpose for which the assembly of the invention is tobe used.

What is claimed is:

l. A method of producing finished castings in continuous operation, saidmethod comprising the steps of:

providing a casting machine and a deburring machine including a closablepattern means;

casting a casting of predetermined configuration in the casting machine;

removing the casting from the casting machine and conveying the same tothe pattern means in the deburring machine while the casting is still inits hot state;

slowly closing the pattern means as the casting cools in said meanswhile applying pressure sufficient to conform the casting onto thepattern means thereby correcting any changes in said configuration ofthe casting as may be caused due to deformation during cooling of thecasting and also locking the casting in position by the pattern means;and

deburring the casting when the cooling thereof and the conforming ontothe pattern means is essentially completed and the casting is locked inposition by the pattern means.

2. A device for producing finished castings in continuous operation,said device comprising:

a casting machine for casting therein a casting of predeterminedconfiguration and a deburring machine for truing and deburring therein acasting cast in the casting machine fixedly coupled to each other, saidcasting machine including means for closing and opening said machine forremoving therefrom a casting and said deburring machine includingpattern means including two parts movable relative to each other forplacing a casting therebetween, means for opening the pattern means forinserting thereinto a casting removed from the casting machine and meansfor pressure closing the pattern means, said pressure closing pressingthe casting into conformity with the contours of the pattern partsthereby truing the casting to said predetermined configuration and alsolocking the casting in position;

conveying means including gripping means for removing castings from thecasting machine and delivering the same between the parts of the patternmeans; and

cycling control means sequentially actuating the opening and closingmeans of the casting machine for opening the conveying means forwithdrawing, one by one, castings while still hot from the castingmachine and delivering the same to the pattern means, actuating theopening and closing means of the pattern means for first opening andthen slowly pressure closing the pattern means to conform the casting tothe pattern means as the casting cools, actuating the deburring means,and actuating the opening and closing means of the pattern means forreopening said means.

3. The device according to claim 2 wherein said deburring means comprisecushioning holder means for holding the casting in position while beingdeburred.

4. The device according to claim 2 wherein said conveying means compriseguide means for guiding the castings as they are being delivered fromthe casting machine to the deburring machine under the control of saidcontrol means, and further comprising machining means also controlled bysaid control means for machining castings after having been deburred bythe deburring means.

5. The device according to claim 4 wherein said machining means compriselubricating means.

6. The device according to claim 4 wherein said machining means comprisesurface finishing means.

7. The device according to claim 1 wherein said two parts of the patternmeans define therebetween a cavity matching the contour of a casting inits cool state, said means for opening and closing the pattern meansincluding adjustable pressure means for controlling the pressure withwhich said pattern parts are moved toward said closed position.

8. The device according to claim 7 and comprising yieldable supportmeans for each of said pattern parts.

9. The device according to claim 7 and comprising cooling means forcooling said pattern parts to accelerate the cooling of a castinginserted thereinto.

10. The device according to claim 1 wherein each casting when withdrawnfrom the casting machine comprises a laterally protruding burr, each ofsaid burrs being dimensioned to block movement of the two parts of thepattern means into the closed position while and when the expansion of acasting due to the casting heat is above a predetermined limit and torelease the pattern parts for movement into the closed position inresponse to shrinking of the casting below said limit due to cooling.

1. A method of producing finished castings in continuous operation, saidmethod comprising the steps of: providing a casting machine and adeburring machine including a closable pattern means; casting a castingof predetermined configuration in the casting machine; removing thecasting from the casting machine and conveying the same to the patternmeans in the deburring machine while the casting is still in its hotstate; applying sufficient pressure to slowly close the pattern means asthe casting cools in said means thereby conforming the casting to thepattern means and thus correcting any changes in said configuration ofthe casting as may be caused due to deformation during cooling of thecasting and also locking the casting in position by the pattern means;and deburring the casting when the cooling thereof and the conformingonto the pattern means is essentially completed and the casting islocked in position by the pattern means.
 2. A device for producingfinished castings in continuous operation, said device comprising: acasting machine for casting therein a casting of predeterminedconfiguration and a deburring machine for truing and deburring therein acasting cast in the casting machine fixedly coupled to each other, saidcasting machine including means for closing and opening said machine forremoving therefrom a casting and said deburring machine includingpattern means including two parts movable relative to each other forplacing a casting therebetween, means for opening the pattern means forinserting thereinto a casting removed from the casting machine and meansfor applying sufficient pressure to close the pattern means, saidclosing shaping the casting into conformity with the contours of thepattern parts thereby truing the casting to said predeterminedconfiguration and also locking the casting in position; conveying meansincluding gripping means for removing castings from the casting machineand delivering the same between the parts of the pattern means in thedeburring machine; deburring means included in said deburring machinefor deburring a casting locked between said pattern means; and cyclingcontrol means sequentially actuating the opening and closing means ofthe casting machine for openiNg the conveying means for withdrawing, oneby one, castings while still hot from the casting machine and deliveringthe same to the pattern means, actuating the opening and closing meansof the pattern means for first opening and then slowly closing thepattern means to conform the casting to the pattern means as the castingcools, actuating the deburring means, and actuating the opening andclosing means of the pattern means for reopening said means.
 3. Thedevice according to claim 2 wherein said deburring means comprisecushioning holder means for holding the casting in position while beingdeburred.
 4. The device according to claim 2 wherein said conveyingmeans comprise guide means for guiding the castings as they are beingdelivered from the casting machine to the deburring machine under thecontrol of said control means, and further comprising machining meansalso controlled by said control means for machining castings afterhaving been deburred by the deburring means.
 5. The device according toclaim 4 wherein said machining means comprise lubricating means.
 6. Thedevice according to claim 4 wherein said machining means comprisesurface finishing means.
 7. The device according to claim 2 wherein saidtwo parts of the pattern means define therebetween a cavity matching thecontour of a casting in its cool state, said means for applyingsufficient pressure for opening and closing the pattern means includingadjustable pressure means for controlling the movement of said patternparts toward said closed position.
 8. The device according to claim 7and comprising yieldable support means for each of said pattern parts.9. The device according to claim 7 and comprising cooling means forcooling said pattern parts to accelerate the cooling of a castinginserted thereinto.
 10. The device according to claim 1 wherein eachcasting when withdrawn from the casting machine comprises a laterallyprotruding burr, each of said burrs being dimensioned to block movementof the two parts of the pattern means into the closed position while andwhen the expansion of a casting due to the casting heat is above apredetermined limit and to release the pattern parts for movement intothe closed position in response to shrinking of the casting below saidlimit due to cooling.